Clinical utility of computed electrocardiographic leads

The standard 12-lead electrocardiogram (ECG) is only one of the possible ways to present the voltage differences between the nine recording electrodes. Other “non-conventional” leads may be constructed by physically connecting two or more electrodes in a different manner or by computation from the digital 12-lead ECG. Examples include bipolar or multipolar precordial leads and bipolar chest leads (between one precordial and one limb electrode). Such leads can remove or decrease noise originating from a limb cable/electrode that is present in the unipolar precordial leads. They can be diagnostically useful in Brugada syndrome and can display QRS fractionation that is not visible in the respective unipolar precordial or limb leads. Multipolar precordial leads sometimes display potentially useful information that is not visible in the respective unipolar leads and in bipolar leads computed from them. In conclusion, these computed ECG leads represent a potentially useful supplement to the conventional 12-lead ECG.